The present invention broadly relates to optical lenses and, more specifically, pertains to a new and improved construction of a high speed infrared wide angle lens system.
Generally speaking, the lens system of the present invention comprises a high speed infrared wide angle lens system having a predeterminate focal length f and comprising an object side section, a middle section and a section on the image side.
Known infrared objectives are either high speed with a small field angle or low speed with a larger field angle. From German Patent Publication No. 2,519,961, published Nov. 20, 1975, there is known an objective with a speed of F/1.5 and a total field angle of 8 degrees. Another objective, known from German Patent Publication No. 1,472,189, published Jan. 9, 1969, has a total field angle of 25 degrees but a speed of only F/1.9, wherein F represents the lens speed of the system.